Amber ACID, is a concrete ſalt obtained from amber; it acts like a feeble acid. It is yet doubtful whether amber be of vegetable origin; many reckon it foſſil.
Aerial ACID (fixed air) is not only combined with water but with many other foſſil ſubſtances, as alkalies (§§ 54, 56), earths (§§ 62, 66), and with ſome metals (§§ 71, 183, 192, 217, 234, 243). It floats uncombined in the atmoſphere. Its ſpecific gravity 0,0018[[18]].
ALKALIES are known by their peculiar lixivial taſte, by their vehement attraction to acids, and by their changing the blue colours of vegetables to a green. In a pure ſtate, as was before obſerved of acids, their attraction to other ſubſtances is ſo ſtrong that they cannot long remain uncombined; and if other acids were wanting, the aerial acid, every where preſent in the atmoſphere, would unite with them: therefore they are always found in a ſtate of combination, unleſs prepared by art.
New acids are daily detected, but no additions have been made to the three ſpecies of alkaly long ſince known.
Vegetable fixed ALKALY, deprived of every acid is not found on the face of the earth; but it is ſometimes met with in combination with the vitriolic acid (§ 44) or the muriatic (§ 46), generally with the nitrous, (§ 45) rarely with the aerial (§ 54).